Loan guarantees have been around since at least the 1940s, when the U.S. government backed loans for homes, farms and businesses for World War II veterans. More recently, the U.S. government has used loan guarantee programs to support the development of clean energy. Projects including the large Ivanpah solar facility in California’s Mojave Desert, a large cellulosic ethanol plant opening this month in Kansas, and—infamously—the failed solar company Solyndra have all been beneficiaries of Department of Energy loan guarantees.

Now, loan guarantees are being considered for a different kind of application: energy access for the roughly 1.3 billion people worldwide who live in the dark. For companies that provide services to the energy-poor, the greatest challenge is not necessarily